The sex ratio of singleton offspring in assisted-conception pregnancies.
OBJECTIVE
To evaluate the effect of intracytoplasmic sperm injection (ICSI) and male factor infertility on the sex ratio in births from assisted reproductive technology.


METHODS
Historic cohort study.


METHODS
Clinic-based data.


METHODS
The study population included 15,164 singleton live births in the Society for Assisted Reproductive Technology national database for 2005 from cycles using ejaculated sperm, categorized by the use of insemination or ICSI and the absence or presence of male factor infertility, and cleavage- versus blastocyst-stage embryo transfers (ETs).


METHODS
None.


METHODS
The probability of a male infant with and without the use of ICSI and in the presence or absence of male factor infertility.


RESULTS
The sex ratio for all U.S. live births in 2005 was 52.5%, versus 48.9% for cleavage-stage and 51.6% for blastocyst-stage embryos. With blastocyst-stage embryos, the sex ratios were 49.6% and 54.9% with and without ICSI and 52.6% and 50.0% with and without male factor infertility, respectively. With cleavage-stage embryos, the sex ratio was not significantly affected by ICSI or male factor infertility, singly or in combination.


CONCLUSIONS
The use of ICSI, particularly with blastocyst-stage embryos, is associated with a decrease in the sex ratio of male infants.
Luke
Barbara
B
Department of Obstetrics, Gynecology, and Reproductive Biology and Department of Epidemiology, Michigan State University, East Lansing, Michigan 48824 , USA. lukeb@msu.edu
Brown
Morton B
MB
Grainger
David A
DA
Baker
Valerie L
VL
Ginsburg
Elizabeth
E
Stern
Judy E
JE
D016241:Child of Impaired Parents / Q000706:statistics & numerical data*; D015331:Cohort Studies; D004624:Embryo Transfer / Q000379:methods; D005260:Female; D005306:Fertilization / Q000502:physiology; D006801:Humans; D007231:Infant, Newborn; D007246:Infertility / Q000628:therapy; D008297:Male; D011247:Pregnancy; D018873:Pregnancy Rate; D027724:Reproductive Techniques, Assisted / Q000706:statistics & numerical data*; D012744:Sex Ratio; D013997:Time Factors